[PATCH 06/10] PM: Add early suspend api.

["Arve Hjønnevåg" <arve@android.com>]

If early-suspend support is enabled, early suspend handlers will be called
when a state other than "on" is written to /sys/power/request_state before
the unlocking "main" wakelock. Writing "on", locks the "main" wakelock and
calls the early-suspend resume handlers.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
---
 Documentation/power/early-suspend.txt |   26 +++++
 include/linux/earlysuspend.h          |   55 ++++++++++
 kernel/power/Kconfig                  |    8 ++
 kernel/power/Makefile                 |    1 +
 kernel/power/earlysuspend.c           |  174 +++++++++++++++++++++++++++++++++
 kernel/power/power.h                  |    5 +
 kernel/power/wakelock.c               |    5 +
 7 files changed, 274 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/power/early-suspend.txt
 create mode 100755 include/linux/earlysuspend.h
 create mode 100644 kernel/power/earlysuspend.c

diff --git a/Documentation/power/early-suspend.txt b/Documentation/power/early-suspend.txt
new file mode 100644
index 0000000..8286d3a
--- /dev/null
+++ b/Documentation/power/early-suspend.txt
@@ -0,0 +1,26 @@
+Early-suspend
+=============
+
+The early-suspend api allows drivers to get notified when user-space writes to 
+/sys/power/request_state to indicate that the user visible sleep state should 
+change. A level controls what order the handlers are called in. Suspend 
+handlers are called in low to high level order, resume handlers are called in 
+the opposite order. 
+
+Four levels are defined:
+EARLY_SUSPEND_LEVEL_BLANK_SCREEN:
+  On suspend the screen should be turned off but the framebuffer must still be
+  accessible. On resume the screen can be turned back on.
+
+EARLY_SUSPEND_LEVEL_STOP_DRAWING:
+  On suspend this level notifies user-space that it should stop accessing the 
+  framebuffer and it waits for it to complete. On resume it notifies user-space 
+  that it should resume screen access.
+  Two methods are provided, console switch or a sysfs interface.
+
+EARLY_SUSPEND_LEVEL_DISABLE_FB:
+  Turn off the framebuffer on suspend and back on on resume.
+
+EARLY_SUSPEND_LEVEL_STOP_INPUT:
+  On suspend turn off input devices that are not capable of wakeup or where
+  wakeup is disabled. On resume turn the same devices back on.
diff --git a/include/linux/earlysuspend.h b/include/linux/earlysuspend.h
new file mode 100755
index 0000000..e3d03fb
--- /dev/null
+++ b/include/linux/earlysuspend.h
@@ -0,0 +1,55 @@
+/* include/linux/earlysuspend.h
+ *
+ * Copyright (C) 2007-2008 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _LINUX_EARLYSUSPEND_H
+#define _LINUX_EARLYSUSPEND_H
+
+#include <linux/list.h>
+
+/* The early_suspend structure defines suspend and resume hooks to be called
+ * when the user visible sleep state of the system changes, and a level to
+ * control the order. They can be used to turn off the screen and input
+ * devices that are not used for wakeup.
+ * Suspend handlers are called in low to high level order, resume handlers are
+ * called in the opposite order. If, when calling register_early_suspend,
+ * the suspend handlers have already been called without a matching call to the
+ * resume handlers, the suspend handler will be called directly from
+ * register_early_suspend. This direct call can violate the normal level order.
+ */
+enum {
+	EARLY_SUSPEND_LEVEL_BLANK_SCREEN = 50,
+	EARLY_SUSPEND_LEVEL_STOP_INPUT = 75,
+	EARLY_SUSPEND_LEVEL_STOP_DRAWING = 100,
+	EARLY_SUSPEND_LEVEL_DISABLE_FB = 150,
+};
+struct early_suspend {
+#ifdef CONFIG_EARLYSUSPEND
+	struct list_head link;
+	int level;
+	void (*suspend)(struct early_suspend *h);
+	void (*resume)(struct early_suspend *h);
+#endif
+};
+
+#ifdef CONFIG_EARLYSUSPEND
+void register_early_suspend(struct early_suspend *handler);
+void unregister_early_suspend(struct early_suspend *handler);
+#else
+#define register_early_suspend(handler) do { } while (0)
+#define unregister_early_suspend(handler) do { } while (0)
+#endif
+
+#endif
+
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index e784014..ccc55be 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -151,6 +151,14 @@ config USER_WAKELOCK
 	  to create, lock and unlock a wakelock. The wakelock will be
 	  deleted when the device is closed.
 
+config EARLYSUSPEND
+	bool "Early suspend"
+	depends on WAKELOCK
+	default y
+	---help---
+	  Call early suspend handlers when the user requested sleep state
+	  changes.
+
 config HIBERNATION
 	bool "Hibernation (aka 'suspend to disk')"
 	depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 63d30db..d3467b3 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_PM_SLEEP)		+= console.o
 obj-$(CONFIG_FREEZER)		+= process.o
 obj-$(CONFIG_WAKELOCK)		+= wakelock.o
 obj-$(CONFIG_USER_WAKELOCK)	+= userwakelock.o
+obj-$(CONFIG_EARLYSUSPEND)	+= earlysuspend.o
 obj-$(CONFIG_HIBERNATION)	+= swsusp.o disk.o snapshot.o swap.o user.o
 
 obj-$(CONFIG_MAGIC_SYSRQ)	+= poweroff.o
diff --git a/kernel/power/earlysuspend.c b/kernel/power/earlysuspend.c
new file mode 100644
index 0000000..4cdca39
--- /dev/null
+++ b/kernel/power/earlysuspend.c
@@ -0,0 +1,174 @@
+/* kernel/power/earlysuspend.c
+ *
+ * Copyright (C) 2005-2008 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/earlysuspend.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/rtc.h>
+#include <linux/syscalls.h> /* sys_sync */
+#include <linux/wakelock.h>
+#include <linux/workqueue.h>
+
+#include "power.h"
+
+enum {
+	DEBUG_SUSPEND = 1U << 0,
+	DEBUG_HANDLERS = 1U << 1,
+};
+static int debug_mask;
+module_param_named(debug_mask, debug_mask, int, S_IRUGO | S_IWUSR | S_IWGRP);
+
+static DEFINE_MUTEX(early_suspend_lock);
+static LIST_HEAD(early_suspend_handlers);
+static void early_suspend(struct work_struct *work);
+static void late_resume(struct work_struct *work);
+static DECLARE_WORK(early_suspend_work, early_suspend);
+static DECLARE_WORK(late_resume_work, late_resume);
+static DEFINE_SPINLOCK(state_lock);
+enum {
+	SUSPEND_REQUESTED = 0x1,
+	SUSPENDED = 0x2,
+	SUSPEND_REQUESTED_AND_SUSPENDED = SUSPEND_REQUESTED | SUSPENDED,
+};
+static int state;
+
+void register_early_suspend(struct early_suspend *handler)
+{
+	struct list_head *pos;
+
+	mutex_lock(&early_suspend_lock);
+	list_for_each(pos, &early_suspend_handlers) {
+		struct early_suspend *e;
+		e = list_entry(pos, struct early_suspend, link);
+		if (e->level > handler->level)
+			break;
+	}
+	list_add_tail(&handler->link, pos);
+	if ((state & SUSPENDED) && handler->suspend)
+		handler->suspend(handler);
+	mutex_unlock(&early_suspend_lock);
+}
+EXPORT_SYMBOL(register_early_suspend);
+
+void unregister_early_suspend(struct early_suspend *handler)
+{
+	mutex_lock(&early_suspend_lock);
+	list_del(&handler->link);
+	mutex_unlock(&early_suspend_lock);
+}
+EXPORT_SYMBOL(unregister_early_suspend);
+
+static void early_suspend(struct work_struct *work)
+{
+	struct early_suspend *pos;
+	unsigned long irqflags;
+	int abort = 0;
+
+	mutex_lock(&early_suspend_lock);
+	spin_lock_irqsave(&state_lock, irqflags);
+	if (state == SUSPEND_REQUESTED)
+		state |= SUSPENDED;
+	else
+		abort = 1;
+	spin_unlock_irqrestore(&state_lock, irqflags);
+
+	if (abort) {
+		if (debug_mask & DEBUG_SUSPEND)
+			pr_info("early_suspend: abort, state %d\n", state);
+		mutex_unlock(&early_suspend_lock);
+		goto abort;
+	}
+
+	if (debug_mask & DEBUG_SUSPEND)
+		pr_info("early_suspend: call handlers\n");
+	list_for_each_entry(pos, &early_suspend_handlers, link) {
+		if (pos->suspend) {
+			if (debug_mask & DEBUG_HANDLERS)
+				pr_info("early_suspend: call %pF\n",
+					pos->suspend);
+			pos->suspend(pos);
+			if (debug_mask & DEBUG_HANDLERS)
+				pr_info("early_suspend: %pF returned\n",
+					pos->suspend);
+		}
+	}
+	mutex_unlock(&early_suspend_lock);
+
+	if (debug_mask & DEBUG_SUSPEND)
+		pr_info("early_suspend: sync\n");
+
+	sys_sync();
+abort:
+	spin_lock_irqsave(&state_lock, irqflags);
+	if (state == SUSPEND_REQUESTED_AND_SUSPENDED)
+		wake_unlock(&main_wake_lock);
+	spin_unlock_irqrestore(&state_lock, irqflags);
+}
+
+static void late_resume(struct work_struct *work)
+{
+	struct early_suspend *pos;
+	unsigned long irqflags;
+	int abort = 0;
+
+	mutex_lock(&early_suspend_lock);
+	spin_lock_irqsave(&state_lock, irqflags);
+	if (state == SUSPENDED)
+		state = 0; /* clear SUSPENDED */
+	else
+		abort = 1;
+	spin_unlock_irqrestore(&state_lock, irqflags);
+
+	if (abort) {
+		if (debug_mask & DEBUG_SUSPEND)
+			pr_info("late_resume: abort, state %d\n", state);
+		goto abort;
+	}
+	if (debug_mask & DEBUG_SUSPEND)
+		pr_info("late_resume: call handlers\n");
+	list_for_each_entry_reverse(pos, &early_suspend_handlers, link)
+		if (pos->resume) {
+			if (debug_mask & DEBUG_HANDLERS)
+				pr_info("early_suspend: call %pF\n",
+					pos->resume);
+			pos->resume(pos);
+			if (debug_mask & DEBUG_HANDLERS)
+				pr_info("early_suspend: %pF returned\n",
+					pos->resume);
+		}
+	if (debug_mask & DEBUG_SUSPEND)
+		pr_info("late_resume: done\n");
+abort:
+	mutex_unlock(&early_suspend_lock);
+}
+
+void request_early_suspend_state(bool on)
+{
+	unsigned long irqflags;
+	int old_sleep;
+
+	spin_lock_irqsave(&state_lock, irqflags);
+	old_sleep = state & SUSPEND_REQUESTED;
+	if (!old_sleep && !on) {
+		state |= SUSPEND_REQUESTED;
+		queue_work(suspend_work_queue, &early_suspend_work);
+	} else if (old_sleep && on) {
+		state &= ~SUSPEND_REQUESTED;
+		wake_lock(&main_wake_lock);
+		queue_work(suspend_work_queue, &late_resume_work);
+	}
+	spin_unlock_irqrestore(&state_lock, irqflags);
+}
+
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 9468679..7d8538d 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -230,3 +230,8 @@ extern struct workqueue_struct *suspend_work_queue;
 extern struct wake_lock main_wake_lock;
 void request_suspend_state(suspend_state_t state);
 #endif
+
+#ifdef CONFIG_EARLYSUSPEND
+/* kernel/power/earlysuspend.c */
+void request_early_suspend_state(bool on);
+#endif
diff --git a/kernel/power/wakelock.c b/kernel/power/wakelock.c
index c396b58..5048ad3 100644
--- a/kernel/power/wakelock.c
+++ b/kernel/power/wakelock.c
@@ -593,10 +593,15 @@ void request_suspend_state(suspend_state_t state)
 			tm.tm_hour, tm.tm_min, tm.tm_sec, ts.tv_nsec);
 	}
 	requested_suspend_state = state;
+
+#ifdef CONFIG_EARLYSUSPEND
+	request_early_suspend_state(state == PM_SUSPEND_ON);
+#else
 	if (state == PM_SUSPEND_ON)
 		wake_lock(&main_wake_lock);
 	else
 		wake_unlock(&main_wake_lock);
+#endif
 	spin_unlock_irqrestore(&state_lock, irqflags);
 }
 
-- 
1.6.1

_______________________________________________
linux-pm mailing list
linux-pm@lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/linux-pm